I am getting Popup mesage something like

You have chosen to open

Update

which is a:application/json From : http://localhost:1234

which ok cancel buttons..

I am using this code to run..

   [HttpPost]
        public JsonResult MEdit(ExpenseBE e)
        {
            var cache = CacheFactory.GetCacheManager();
            string F_ACTION = "U";
            string F_DEBUG = "Y";
            var excUpdateStatus = false;
            for (int i = 0; i <= cache.Count; i++)
            {
                var x = (ExpenseBE)cache.GetData("a" + i);
                if (x != null)
                {
                    string Resolutioncode = e.Exception.ResolutionCode;
                    string reasoncode = e.Exception.ReasonCode;
                    string actioncode = e.Exception.ActionCode;
                    e.Exception.ExceptionID = x.Exception.ExceptionID;
                    e.Exception.ReasonCode = reasoncode;
                    e.Exception.ReasonCode = Resolutioncode;
                    e.Exception.ActionCode = actioncode;
                    e.Exception.Sequence = x.Exception.Sequence;
                    e.Exception.FollowupDate = x.Exception.FollowupDate;
                    e.Exception.IOL = x.Exception.IOL;
                    e.Exception.LastUpdateUser = User.Identity.Name.ToUpper().Remove(0, 4);
                    excUpdateStatus = common.UpdateException(e.Exception, F_ACTION, F_DEBUG);

                }
            }
            return Json(excUpdateStatus.ToString()); 
        }

and my view is

<%@ Control Language="C#" Inherits="System.Web.Mvc.ViewUserControl<NorthernTrust.ATP.iTool.Core.Business.Entities.Specialist.ExpenseBE>" %>

<% using (Html.BeginForm("MEdit", "expense", FormMethod.Post)) 
   { %>
<%= Html.ValidationSummary(true)%>

<fieldset class="clearfix" id="fieldset-exception">
    <legend>Mass Edit Exception Information</legend>
    <div class="fiveper">
    <label for="ExceptionStatus">
            Status:
            <span> </span>
        </label>
         <label for="ResolutionCode">
            Resolution:
            <span>
           <%=Html.DropDownListFor(model=>model.Exception.ResolutionCode,new SelectList(Model.LookupCodes["C_EXCPT_RESL"], "Key", "Value"))%>
            </span>
        </label>
         <label for="ReasonCode">
            Reason:
           <span><%=Html.DropDownListFor(model => model.Exception.ReasonCode, new SelectList(Model.LookupCodes["C_EXCPT_RSN"], "Key", "Value"))%></span>
        </label>
         <label for="ExceptionStatus">
            Action Taken:
           <span><%=Html.DropDownListFor(model => model.Exception.ActionCode, new SelectList(Model.LookupCodes["C_EXCPT_ACT"], "Key", "Value"))%></span>
        </label>
    </div>
    <div class="fiveper">
        <label for="FollowupDate">
            Follow-up:
         <span><input type="text" id="exc-flwup-" /></span>
        <%--<%=Html.EditorFor(model=>model.Exception.FollowupDate) %>--%>
        </label>
        <label for="IOL">
            Inquiry #:
            <%=Html.TextBox("Inquiery", ViewData["inq"] ?? "")%>
        </label>
        <label>Comment</label>
        <span>
           <%=Html.TextArea("value") %>
           <%=Html.ValidationMessage("value")%>
          </span>
    </div>
    <br />
    <br />
      <div>
        <button id="btnSelect"  class="button">Select All</button>
        <button id="btnCancel" class="button">Cancel</button>
        <input type="submit" class="button" value="Save" />
        </div>
</fieldset>
<% } %>

<script type="text/javascript">
    $(document).ready(function() {
    $('#btnSelectAll').click(function() {
    function validate_excpt(formData, jqForm, options) {
        var form = jqForm[0];
    }
    $('#btnSelect').click(function() {
        $('#input [type=checkbox]').attr('checked', 'checked');
    });
    // post-submit callback 
    function showResponse(responseText, statusText, xhr, $form) {
        if ('success' == statusText) {
            $('#error-msg span:last').html('<strong>Update successful.</strong>');
        } else {
            $('#error-msg span:last').html('<strong>Update failed.</strong> ' + responseText);
        }
        $('#error-msg').removeClass('hide');
    }

    $('#exc').ajaxForm({
        target: '#error-msg',
        beforeSubmit: validate_excpt,
        success: showResponse,
        dataType: 'json'
    });
    $('.button').button();
    });
        $('.button').button();
        $("input[id^='exc-flwup-']").datepicker({
            duration: '',
            showTime: true,
            constrainInput: true,
            stepMinutes: 30,
            stepHours: 1,
            altTimeField: '',
            time24h: true,
            minDate: 0
        });
        $('#ui-timepicker-div').bgiframe();
    });
</script>

please correct me if i am doing somwhere wrong? thanks